Nanopillar arrays with interfaces for controlled polymer stretching and effective translocation into nanochannels

Abstract

A technique relates to stretching an extensible molecule. The molecule moves through an array of pillars in a flow direction, where the array has an interface connecting a first pillar region and a second pillar region. Stretching the molecule by traversing the molecule in the flow direction through the interface connecting the first pillar region to the second pillar region, such that a first end and a second end of the molecule straddle a straddle pillar, thereby causing the first end to extend along a first path in the second and the second end to extend along a second path. Traversing the molecule stretches the first end and the second end along two different paths. The molecule is further traversed through the array such that the second end follows the first end along the first path, where the stretching causes the molecule to be in an uncoiled state.

What is claimed is: 
     
       1. A method to stretch an extensible molecule flowing in a fluidic device, the method comprising:
 moving a molecule through an array of pillars in a flow direction, wherein the array of pillars are organized to have at least one interface connecting a first pillar region and a second pillar region; 
 stretching the molecule by traversing the molecule in the flow direction through the interface connecting the first pillar region to the second pillar region, such that a first end and a second end of the molecule straddle at least one straddle pillar, thereby causing the first end to extend in the flow direction along a first path in the second pillar region and causing the second end to extend in the flow direction along a second path in the second pillar region, wherein traversing the molecule stretches the first end and the second end along two different paths; and 
 further traversing the molecule through the array of pillars in the flow direction such that the second end follows the first end along the first path in the second pillar region, wherein the stretching causes the molecule to be in an uncoiled state; 
 wherein the interface between the first and second pillar regions is discontinuous, such that the interface is jagged. 
 
     
     
       2. The method of  claim 1 , wherein the first pillar region is homogeneous. 
     
     
       3. The method of  claim 1 , wherein the second pillar region is homogeneous. 
     
     
       4. The method of  claim 1 , wherein pillars in the first and second pillar regions are a diamond shape. 
     
     
       5. The method of  claim 1 , wherein the first pillar region includes first pillars having a first width and the second pillar region includes second pillars having a second width. 
     
     
       6. The method of  claim 5 , wherein the first width of the first pillars is larger than the second width of the second pillars. 
     
     
       7. The method of  claim 6 , wherein the flow direction is from the first pillar region to the second pillar region. 
     
     
       8. The method of  claim 7 , wherein the straddle pillar is in the second pillar region. 
     
     
       9. The method of  claim 8 , wherein straddling of the straddle pillar occurs as the molecule is leaving the first pillar region and entering the second pillar region. 
     
     
       10. The method of  claim 5 , where the molecule is a DNA or RNA molecule of length at least 10 times the second width of the second pillars. 
     
     
       11. A fluidic device having an array of pillars to cause straddling, the device comprising:
 a first pillar region of first pillars, wherein a gap separates the first pillars from one another; 
 a second pillar region of second pillars such that the first and second pillar regions have an interface, wherein a smaller gap separates the second pillars from each other, wherein the first pillars have a larger width than the second pillars; and 
 an interface that is discontinuous between the first pillar region and the second pillar region, such that a point of the second pillars is positioned at the gap of the first pillars at the interface, wherein one or more of the second pillars, positioned at the gap of the first pillars, is configured to act as a straddling pillar. 
 
     
     
       12. A method of fabricating an array of pillars to cause straddling, the method comprising:
 forming a first pillar region of first pillars, wherein a gap separates the first pillars from one another; 
 forming a second pillar region of second pillars such that the first and second pillar regions have an interface, wherein a smaller gap separates the second pillars from each other, wherein the first pillars have a larger width than the second pillars; and 
 forming an interface that is discontinuous between the first pillar region and the second pillar region, such that a point of the second pillars is positioned at the gap of the first pillars at the interface, wherein one or more of the second pillars, positioned at the gap of the first pillars, is configured to act as a straddling pillar. 
 
     
     
       13. The method of  claim 12 , wherein on an opposite side of the second pillar region relative to the first pillar region, nanochannels are formed. 
     
     
       14. The method of  claim 13 , wherein one or more other pillars regions are formed between the second pillar region and the nanochannels. 
     
     
       15. The method of  claim 10 , wherein the first pillars in the first pillar region and the second pillars in the second pillar region are diamond-shaped relative to a flow direction. 
     
     
       16. The device of  claim 11 , wherein on an opposite side of the second pillar region relative to the first pillar region, nanochannels are formed. 
     
     
       17. The device of  claim 16 , wherein one or more other pillars regions are formed between the second pillar region and the nanochannels. 
     
     
       18. The device of  claim 11 , wherein the first pillars in the first pillar region and the second pillars in the second pillar region are diamond-shaped relative to a flow direction. 
     
     
       19. The device of  claim 11 , wherein the gap is twice as large as the smaller gap; and
 wherein a first width of the first pillars is twice as large as a second width of the second pillars.